Potato Review

www.potatoreview.com POTATO REVIEW JULY/AUGUST 2021 33 BLIGHT B ringing new potato varieties to the marketplace is very much a combined e ort, with seed breeders working closely with growers to develop desirable agronomic traits, and the wider supply chain for those crucial characteristics such as dry matter distribution, sugar formation and storability, for example. In parallel, the work of researchers across the globe informs the breeders about the moving target that is blight and puts potential new varieties through their paces in the eld. e James Hutton Institute is one such research body and currently has projects covering everything from pathogen diversity, evolution and phenotyping to host resistance and IPM. e knowledge gleaned from these projects, together with in-house research, inform the work of seed breeders. And this is before growers, like Nick Taylor, start on-farm commercial trials. Fighting blight: What does it take to bring a resistant variety to market? Dr David Cooke, research leader in Cell and Molecular Sciences at the James Hutton Institute is involved in strengthening the industry’s understanding of pathogen populations and how to best use inherent resistance to control late blight in the eld as part of an IPM strategy. “Varietal resistance doesn’t play as big a part in crop protection programmes as it really should,” he says. “It’s a form of protection that lasts; from the seed tubers right through to harvest and beyond. “We are so reliant on fungicides yet pressure to reduce these inputs is mounting, not least from the pathogen itself. Late blight’s ability to reproduce both sexually and asexually means there’s tremendous variability within the population and it’s that variability that gives the pathogen it’s potential to resist fungicide activity - as we saw back in 2017 with the 37_A2 lineage and uazinam.” Know your enemy It is why his work within the Fight Against Blight and Euroblight projects are so important. In 2020, 90 UK growers (FAB scouts) submitted nearly 700 genetic samples of late blight to the team at the James Hutton Institute for analysis. Together with samples gathered across the continent, researchers are able to track the evolution, spread and population growth of di erent genotypes. Work by David’s counterparts such as Dr Alison Lees are able to use the samples to determine sensitivity to active ingredients, as well as the pathogen’s mechanisms to overcome genetic resistance. “Late blight, or Phytophthora infestans, is not a fungus. It’s an oomycete and can reproduce in two ways. “Firstly the sexual cycle. is is where the hyphae of both mating types, A1 and A2 meet in a leaf. It triggers the production of oospores and generates new variation within the pathogen population. ➜